/*
 * Copyright (C) 2010 Yury Kudryashov.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package name.kudryashov.concurrent;

public final class SyncVar<T> {

    private T ref;
    private boolean isSet = false;

    public SyncVar(T ref) {
        this.ref = ref;
        this.isSet = true;
    }

    public SyncVar() {}

    public synchronized T get() throws InterruptedException {
        while(!isSet) {
            wait();
        }
        return ref;
    }

    public synchronized void set(T value) {
        // TODO quick set/unset won't unblock all the threads
        ref = value;
        isSet = true;
        notifyAll();
    }

    public synchronized void unset() {
        ref = null;
        isSet = false;
    }
}